Self-tightening collet



u y 15, 1952 A. J. RICHERT SELF-TIGHTENING COLLET Filed Oct. 12, 1950 Inventor: Abraham J. -Richert,

His Attorney.

Patented July 15, 1952 7 to General Electric. Company,

New York a corporation of Application October: 12, 19'50,--Seriall io;189,786"

1; V 1 This invention relates o collets. and more-particularlyto a self-tightening. V colletwhich will readily -slip'onto' a shaft whenitis. stationary andwhich will firmly gripthe shaft whenever able wh'n'the shaft stops rotating, is highly desirablefo-r such an application. Furthermore, a self-tightening collet is.adlvantageous for other uses, for. ex'a'mple...in. chucks. and: variousotherforms'oidrivesh H An. ohj'ect of thisinvention isto. provide an improved-comet... n Y t ,Anotherobject of this inventionis to provide aseli tightening collet which maybe readily slipped onto a shaft-when itisstationary. and which willfirmly grip the shaft whenever torqueis applied in either direction. v

Further objects and -advantagesvofthis in-- vention will become apparent and-the. invention will he better understood by reference to the following description and the accompanyingdra-wing, and the. features of-novelty-which characterize this. invention Willbe pointed out with particularity in the claims .annexed to and form-aing a part ofithe specification.- Y

, In accordance with. thisinvention; an outersleeve memberis provided having a 'cavity-i ormedther'eimwith an. inner sleeve member-arranged in the. cavity; The. inner sleeve-.member is-pro-' vided with a'. plurality ofv longitudinal slots in which a rollers. are. arranged. n: gripping I collet comprising. alplurali'ty. of. segments equal-in number, to thenumber of .inner sleevemember slots is arranged. within .the inner. sleeve..member and is adapted to slidably engage ashaft insertedtherein;',j. Each off. thesegmentshasa fiat formed] on its outer surface upon which. the. rollers respectively rest. When torque is; appliedto. either the outer sleeve member or the grippingcollet, the; rollers cause. a wedfg'ing. action between. theinner surface. of. the outer sleeve and the. collet. seg-- ments, thus causingitheicollet segments toautomatically grip/I the sha'ftt. This. gripping. continues as long. as torque. ie applied? hdwever, when.

torque is released, the .wedging. actionlc'easesand the collet segments. are'again loosesothat the. device may be readily. remdvedl'iromtheshaft In the diaWirigjEig;llis aiside elevational view-,- par-tly section; illustratingthe improved selftighteningcollet. of this invention; Fig .2; isa crossselctional. view; taken along; the-1ine 2&2

applied; Fig, 3 List a. cross section'al view' similar ,t-o-Fig'. 2il1ustrating the relative positionof parts i in the driving position; and; Fig. 4*illustrates the application: of: the improved. self-tightening collet ofthis invention: with: aftest pulley;

Referring; now to Fig.1, there isv shown an outersleeve member having a cavity 2' formed therein,- preferably "provided with ai ground inner surface 3; The-exterior surface of the outer sleeve member. I is provided with. an. outwardly tapering portion 4 and: an. interior. shoulder por tion 5. Threa'dsG are'formed'on' theeX-terior surface of; the outer-"sleeve member I on. its end remote." fromrthe outwardly" tapering portion: 4 in order'to'secure a device to the collet suchas a pulley or :a-chu'ck. Arranged: irrthe cavity"2 of the outer sleeve' member. .l? and spaced from the inner; surface 3=thereof is arr inner "sleeve member 1 provided! with a plurality of longitudinal slots 8 formed therein. Arranged within the inner sleeve member: 1 is a" gripping. 'collet formed of a plurality i of: individual. and spaced-apart :collet segmentsequa-lrin numberto the islets 8' in the innersleeve member T. In: the. normal: position,

as shoWn'intFig. 2;.t e ne'r surfaces of: the collet segments ,9iare adapted:v td .slidiriglyi' engage a shaft orrtool' shank I0 soithat theijdevice maybe readily slid onto the shaft Whenrit is stationary.

Each, of. the-collet. segments-971s. formed with than: the spacing;:loetween. theinner surface 3: of

the outer sleeve member: andfthe; outer. surfaces of the. collet segmentsifi: Therefore, as shown in Fig. 2; withino'torquerappliedfito the: device; the rollers l2 will-restreither ontthe :fiatsrzl or "on the;

. inner surface? 3 of the outer" sleeveimember i,

depending upon their relative position. As -will be seen,- withsparticul'ar referencei-to Eigamthe inner sleeve member??? accurately spaces the roll ers I21 so; that: theye are normally respectively alignedswith; the unidepoints of thfiats l I i; As

shown in Fig: 3;. whenitorquelis applied to either theouter. sleeve? men-1b err- .1 far the ml t; g t 9,:the rollers-1 l2 iare rolleditowardthe-outer extremities o f thexfiatsz'l i and thus cause -a vvedging action betweeni the' innersurface- 3 of the outer sleeve members! and" the outerextremities of the flats I l-,. causingthe: colletlsegm'ents ir-to be forced against th'e'j'shaft' 1mm: automatically-produce a;

grippinggactionix It 'willlbfeireadiiy seen-that this erippingcactionlwill continue as long-as torqu is bein applied: to. th device? and also that i the device is operable in either direction, i. e., for either direction of rotation of the shaft E or of the outer-sleeve member I. When torque ceases to be applied, 1. e., when either the shaft [0 or the outer sleeve member 1 stops rotating, the wedging action of the rollers l2 ceases and. the pressure on the collet segments 9 is released. Therefore, the sliding engagement of the collet segments 9 with the shaft 10 is restored and the device can be readily removed from the shaft.

In the assembly of the device, a stop washer I3 is provided at the base of the cavity 2 abutting the shoulder portion of the outer sleeve member l. The inner sleeve member 1 and collet se ments 9 are seated against the stop washer I3 and are retained inassembled position by an annular retainer [4 and snap ring [5 positioned in a suitable annular groove [6 formedin the inner surface 3 of the cavity 2.

- Referring now to Fig. 4, there is shown a test pulley I! mounted on the outer'sleeve member I. The pulley H is held on the outer sleeve member I by means of a pin 1 8 arranged in openingl 9 in the tapered portion 4 of the outer sleeve member I and engaging a keyway 20 in the hub 21 of the pulley IT. A nut 22 threadingly engages the thread 6 on the outer sleeve member 5 and retains. the pulley I! on the outer sleeve member. It will now be readily apparent that the test pulley I1, which may be provided with a suitable groove 23 in which a V-belt 24 may be arranged, by virtue of its mounting on the selftightening collet described above, may be slid onto the shaft [0 of a test motor 25 when the shaft is stationary and will be tightly secured to the shaft when torque is applied to either the shaft or the pulley; Whenever the torque ceases, the gripping action of the collet ceases and the test pulley with its attached self-tightening collet may be readily removedfrom the shaft.

' It will now be readily apparent that this invention provides an improved collet device which may be readily slid onto a shaft or tool shank and which will automatically tightly grip the shaft or shank whenever torque is applied. The gripping action is released automatically whenever the torque is released permitting the device to be readily removed from the shaft without the necessity of utilizing any tools and furthermore the device is operable in either direction of rotation.

While I have illustrated and described a specific embodiment of this invention, further modifications and improvements will occur to those skilled in the art, and I desire-it to be understood, therefore, that this invention is not limited to the embodiment shown and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of the claims. What I claim as new and desire to secure by Letters Patent of the United States is:

1. 'A self-tightening collet comprising an outer inner sleeve member slots and adapted to rest sleeve member having a cavity formed therein, 7

an inner sleeve member arranged in said cavity and having a plurality of longitudinal slots formed therein, a gripping collet arranged within said inner sleeve member comprising a plurality of segments equal in number to said inner sleeve member slots and. respectively having their inner circumferential surfaces arranged to receive and circumferentially grip a shaft removably inserted therein, each of said segments having a fiat formed on its outer surface, and a plurality of rollers respectively arranged in said on said collet segment flats whereby application of torque to said outer sleeve member or said gripping collet segments causes said rollers to wedge between the inner surface of said outer sleeve member and said collet segment flats so that said collet segments tightly grip said shaft.

2. A self-tightening collet comprising an outer sleeve member having a cylindrical cavity formed therein, a cylindrical inner sleeve member arranged in' said cavity and having a plurality of evenily spaced longitudinal slots formed therein, a cylindrical gripping collet arranged within said inner sleeve member com prising a plurality of semi-circular segments equal in number to said inner sleeve member slots and respectively having their inner circumferential surfaces arranged to receive and initially circumferentially grip a shaft removably inserted therein with a slip fit, each of said segments having a fiat formed on its outer surface, and. a plurality of rollers respectively arranged in said inner sleeve member slots and adapted to rest on said collet segment flats whereby application of torque to said outer sleeve member or said gripping collet segments causes said rollers to wedge between the inner surfaceof said outer sleeve member and said collet segment flats so that said collet segments tightly grip said shaft.

3. A self-tightening collet comprising an outer sleeve member having a cylindrical cavity formed therein, a cylindrical inner sleeve member arranged in said cavity and having a plurality of evenly spaced longitudinal slots formed therein, a cylindrical gripping collet arranged within said inner sleeve member comprising a plurality of semi-circular segments equal in number to said inner sleeve member slots and respectively having their inner circumferentialsurfaces arranged to receive and initially circumferentially grip a shaft removably inserted therein withv a slip fit, means for retaining said inner sleeve member and said gripping collet within said outer sleeve member cavity, each of said segments having a flat formed on its outer surface, and a plurality of rollers respectively arranged in said inner sleeve member slots and adapted to rest on said collet segment flats whereby application of torque to said outer sleeve member or said gripping collet segments causes said rollers to Wedge between the inner surface .of said outer sleeve member and said collet segment flats so that said collet segments tightly grip said shaft.

4. A self-tightening collet comprising an outer sleeve member having acylindricalcavity formed therein, a cylindrical inner sleeve member arranged in said cavity and spaced from the inner surface of said outer sleeve member, said inner.

sleeve member having a plurality of evenly spaced longitudinalslots formed: therein, a cylindrical gripping collet arranged within said inner sleeve member and spaced therefrom comprising a plurality of spaced-apart semi-circular segments equal in number of saidinner sleeve member slots and respectively having their inner circumferential surfaces arranged to receive and initially circumferentially grip a shaft removably inserted thereinwith apslip fit, each of said segments having a flat formed on its outer surface, and a plurality of rollers respectively arranged in said inner sleeve member slots and retained thereby; the diameter of said rollers being greater than the thickness of said inner tween the inner surface of said outer sleeve memher and the outer surface of said collet se ments, and less than the distance between the inner surface of said outer sleeve member and the mid-point of said collet segment flats whereby application of torque to said outer sleeve member or said gripping collet segments causes said rollers to wedge between the inner surface of said outer sleeve member and the outer excollet segments tightly grip said shaft.

5. A self-tightening collet comprising an outer sleeve member, an inner sleeve member arranged within said outer sleeve member and having a plurality of longitudinal slots formed therein, a gripping collet arranged within said inner sleeve member and comprising a plurality of segments respectively having their inner circumferential surfaces arranged to receive and, circumferential- 1y grip a shaft removably inserted therein, each of said segments having a portion of its outer surface formed with a smaller radial dimension than the remaining portion thereof, and a plurality of rollers respectively arranged in said inner sleeve member slots adapted to normally rest on either the inner surface of said outer sleeve member or the mid-points of said first-named segment portions whereby application of torque to said outer sleeve member or said collet segments causes said rollers to wedge between the inner surface of said outer sleeve member and said first-named segment portions so that said collet segments tightly grip said shaft.

6. A self-tightening collet comprising an outer member, gripping means arranged within said outer member and having its inner circumferential surface arranged to receive and initially circumferentially grip a shaft removably inserted therein with a slip fit, said gripping means having a plurality of surfaces having a smaller radial dimension than the remaining outer surface thereof, a plurality of rolling means arranged between said gripping means surfaces and the inner surface of said outer member, and means for retaining and spacing said rolling means whereby application of torque to said outer member or said gripping means causes said rolling means to wedge between the inner surface of said outer member and said gripping means surfaces so that said gripping means tightly engages said shaft.

ABRAHAM J. RICI-IERT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date 

